sched_clock: delay using sched_clock()
Some arch's can't handle sched_clock() being called too early - delay
this until sched_clock_init() has been called.
Reported-by: Bill Gatliff <bgat@billgatliff.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Nishanth Aravamudan <nacc@us.ibm.com>
CC: Russell King - ARM Linux <linux@arm.linux.org.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ea436bc..5850bfb 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1551,16 +1551,10 @@
extern unsigned long long sched_clock(void);
+extern void sched_clock_init(void);
+extern u64 sched_clock_cpu(int cpu);
+
#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-static inline void sched_clock_init(void)
-{
-}
-
-static inline u64 sched_clock_cpu(int cpu)
-{
- return sched_clock();
-}
-
static inline void sched_clock_tick(void)
{
}
@@ -1573,8 +1567,6 @@
{
}
#else
-extern void sched_clock_init(void);
-extern u64 sched_clock_cpu(int cpu);
extern void sched_clock_tick(void);
extern void sched_clock_idle_sleep_event(void);
extern void sched_clock_idle_wakeup_event(u64 delta_ns);
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index 074edc9..204991a 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -42,6 +42,8 @@
return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
}
+static __read_mostly int sched_clock_running;
+
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
struct sched_clock_data {
@@ -70,8 +72,6 @@
return &per_cpu(sched_clock_data, cpu);
}
-static __read_mostly int sched_clock_running;
-
void sched_clock_init(void)
{
u64 ktime_now = ktime_to_ns(ktime_get());
@@ -248,6 +248,21 @@
}
EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
+#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+
+void sched_clock_init(void)
+{
+ sched_clock_running = 1;
+}
+
+u64 sched_clock_cpu(int cpu)
+{
+ if (unlikely(!sched_clock_running))
+ return 0;
+
+ return sched_clock();
+}
+
#endif
unsigned long long cpu_clock(int cpu)